Britain's aid budget can be expected to rise in line with higher growth projections as outlined by George Osborne in his autumn statement.

The chancellor revised growth figures upwards to 1.4% from 0.6% for 2013 and to 2.4% from 1.8% for 2014. As Osborne reaffirmed that Britain this year would meet its target of spending 0.7% of gross national income (GNI) on development, the money for Britain's official development assistance (ODA) will rise accordingly.

In 2012, UK aid came to £8.7bn or 0.56% of GNI, an increase of £137m (2%) on 2011 levels. Meeting the 0.7% target in 2013 would mean that Britain's ODA will rise to £11.2bn this year, £11.9bn in 2014 and £12.3bn in 2015, according to One, the anti-poverty group.

"Britain's faltering growth since 2010 means that aid to developing countries has been cut by up to £1.2bn from planned levels," said Adrian Lovett, One's Europe executive director. "Today's good economic news should begin to reverse that decline, with an additional £610m for aid in the next two years, which is enough to fund more than 27m vaccinations, saving 900,000 lives."

However, the autumn statement revealed that the budget for the Department for International Development (DfID) would be kept at current levels. This means that any extra development money will be handled by other government departments. Not all aid money goes through DfID. Much of the money on humanitarian assistance for the Philippines will have gone through the Ministry of Defence, which sent ships to help in the aftermath of typhoon Haiyan.

DfID handles most of Britain's aid money, with £7.5bn going through the department in 2012, but other departments are seeing an increase in the aid they spend too. According to the last figures available from the Office of National Statistics, the share of non-DfID aid increased in 2012 to 13.4%, with the beneficiaries of the largest funds being the Foreign and Commonwealth Office (£282m) and the Department of Energy and Climate Change (£246m).

Only spending with "the promotion of the economic development and welfare of developing countries" as its main goal is eligible, but in practice the rules, set in 1969, have allowed donors to count a wide range of activities. The UK, for example, counted £3m worth of pension payments to former colonial officers as ODA last year.

The Dac is considering ideas on whether, and how, to change the official ODA definition, with the aim of setting concrete proposals by late 2014. David Cameron, Britain's prime minister, has already indicated that he would like to count money for peacekeeping defence operations as ODA. In February, he said he would like to see more of the aid budget diverted to defence by building up the "conflict pool" that is already used by the Ministry of Defence and international development department.

Aid experts said they would be closely monitoring how any increase in development money will be spent.

"The UK government's continued commitment to meeting its 0.7% target to ODA this year means that the UK will need to increase its budget for ODA by an additional £119m as a result of higher national income due to faster growth since the budget in March," said Harpinder Collacott, director of engagement at Development Initiatives, a research group. "This increase could result in greater ODA spending across government, not just DfID. The UK's role in providing recent emergency assistance to the Philippines for the post-typhoon recovery effort will have contributed to the UK's spending on ODA in 2013. Development Initiatives will be monitoring the data closely as it becomes available to provide transparency and accountability of government development spending."

Natalie Duck, head of policy and campaigns at Concern Worldwide, said: "It is positive that the UK has met its promise to spend 0.7% of national income on international development, but this commitment still needs to be enshrined in law to make it legally binding in the years to come. We need to make sure that aid money is spent fighting poverty in the world's poorest communities. This means guarding against the diversion of aid money to support military activity and a stronger focus on the world's poorest regions and a reduced investment in middle income countries."